build(tsc-wrapped): use tsickleCompilerHost for initial file load

In order for tsickle's new support for input source maps to work, the tsickleCompilerHost must be used for the initial load of source files, since that's when the inline source maps are read and stripped.

tools/@angular/tsc-wrapped/src/main.ts

@@ -86,29 +86,6 @@ export function main(
       parsed.fileNames.push(name);
     }
 
-    const program = createProgram(host);
-    const errors = program.getOptionsDiagnostics();
-    check(errors);
-
-    if (ngOptions.skipTemplateCodegen || !codegen) {
-      codegen = () => Promise.resolve(null);
-    }
-
-    if (diagnostics) console.time('NG codegen');
-    return codegen(ngOptions, cliOptions, program, host).then(() => {
-      if (diagnostics) console.timeEnd('NG codegen');
-      let definitionsHost = host;
-      if (!ngOptions.skipMetadataEmit) {
-        definitionsHost = new MetadataWriterHost(host, ngOptions);
-      }
-      // Create a new program since codegen files were created after making the old program
-      let programWithCodegen = createProgram(definitionsHost, program);
-      tsc.typeCheck(host, programWithCodegen);
-
-      let preprocessHost = host;
-      let programForJsEmit = programWithCodegen;
-
-
     const tsickleCompilerHostOptions: tsickle.Options = {
       googmodule: false,
       untyped: true,
@@ -123,8 +100,30 @@ export function main(
       fileNameToModuleId: (fileName) => fileName,
     };
 
-      const tsickleCompilerHost = new tsickle.TsickleCompilerHost(
+    const tsickleCompilerHost =
-          preprocessHost, ngOptions, tsickleCompilerHostOptions, tsickleHost);
+        new tsickle.TsickleCompilerHost(host, ngOptions, tsickleCompilerHostOptions, tsickleHost);
+
+    const program = createProgram(tsickleCompilerHost);
+
+    const errors = program.getOptionsDiagnostics();
+    check(errors);
+
+    if (ngOptions.skipTemplateCodegen || !codegen) {
+      codegen = () => Promise.resolve(null);
+    }
+
+    if (diagnostics) console.time('NG codegen');
+    return codegen(ngOptions, cliOptions, program, host).then(() => {
+      if (diagnostics) console.timeEnd('NG codegen');
+      let definitionsHost: ts.CompilerHost = tsickleCompilerHost;
+      if (!ngOptions.skipMetadataEmit) {
+        definitionsHost = new MetadataWriterHost(tsickleCompilerHost, ngOptions);
+      }
+      // Create a new program since codegen files were created after making the old program
+      let programWithCodegen = createProgram(definitionsHost, program);
+      tsc.typeCheck(host, programWithCodegen);
+
+      let programForJsEmit = programWithCodegen;
 
       if (ngOptions.annotationsAs !== 'decorators') {
         if (diagnostics) console.time('NG downlevel');
@@ -133,7 +132,6 @@ export function main(
         // metadataWriter
         programForJsEmit = createProgram(tsickleCompilerHost);
         check(tsickleCompilerHost.diagnostics);
-        preprocessHost = tsickleCompilerHost;
         if (diagnostics) console.timeEnd('NG downlevel');
       }
 

tools/@angular/tsc-wrapped/test/main.spec.ts

@@ -264,4 +264,35 @@ describe('tsc-wrapped', () => {
         })
         .catch(e => done.fail(e));
   });
+
+  it('should accept input source maps', (done) => {
+    write('tsconfig.json', `{
+      "compilerOptions": {
+        "experimentalDecorators": true,
+        "types": [],
+        "outDir": "built",
+        "declaration": true,
+        "moduleResolution": "node",
+        "target": "es2015",
+        "sourceMap": true
+      },
+      "angularCompilerOptions": {
+        "annotateForClosureCompiler": true
+      },
+      "files": ["test.ts"]
+    }`);
+    // Provide a file called test.ts that has an inline source map
+    // which says that it was transpiled from a file other_test.ts
+    // with exactly the same content.
+    write('test.ts', `const x = 3;
+//# sourceMappingURL=data:application/json;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbIm90aGVyX3Rlc3QudHMiXSwibmFtZXMiOltdLCJtYXBwaW5ncyI6IkFBQUEsTUFBTSxFQUFFLEVBQUUsQ0FBQyIsImZpbGUiOiIuLi90ZXN0LnRzIiwic291cmNlUm9vdCI6IiJ9`);
+
+    main(basePath, {basePath})
+        .then(() => {
+          const out = readOut('js.map');
+          expect(out).toContain('"sources":["other_test.ts"]');
+          done();
+        })
+        .catch(e => done.fail(e));
+  });
 });